Plastics

Question 0

What is a thermoset plastic?

Answer 0

These undergo a chemical change resulting in them becoming permanently rigid therefore they cannot be reheated and reshaped

Question 1

What is a thermoplastic?

Answer 1

Materials which can be repeatedly reheated and remoulded

Question 2

What is a elastomer?

Answer 2

These are polymers that have good elasticity therefore they can be distorted under pressure but will return to their original shape when the pressure is removed.

Question 3

Name some general properties of plastics?

Answer 3

Good electrical and thermal insulators
Good strength to weight ratio
Good atmospheric and chemical corrosion resistance
Fairly low melting points
Lightweight

Question 4

What are the advantages of injection moulding?

Answer 4

Very complex 3d shapes can be produced
High volumes can be produced with consistent quality
Metal inserts can be included in the item being produced

Question 5

What is the use of ABS and why is it used for that usage?

Answer 5

Use- kitchen products,mobile telephone cases,PC monitor cases,safety helmets,toys,car parts and domestic telephones

Why:high impact strength,good toughness with good strength,scratch resistant,lightweight,durable

Question 6

Name me a example of a filler and why is it used?

Answer 6

Sawdust,wood flour,crushed Quartz,limestone
Used to reduce bulk of the plastic and help reduce costs.Some fillers can increase strength and hardness of the polymer by removing brittleness.

Question 7

What is meant by biodegradable?

Answer 7

Materials that will break down with the aid of natural processes such as sunlight and rain.

Question 8

What is the advantages and disadvantages of blow moulding?

Answer 8

Advantage-rapid method of producing hollow objects with narrow necks.
Non circular shapes can be produced
Disadvantages-moulds can be expensive,difficult to produce re-entrant shapes
Triangular shaped bottles are difficult to produce

Question 9

What is blow moulding?

Answer 9

A process of manufacturing thermoplastic materials into re-entrant shapes with a single opening.

Question 10

What is the advantage and disadvantage of thermoforming?

Answer 10

Advantage-Low cost process
Good for smooth shapes with additional detail
Disadvantage-limited to simple designs
Trimming usually needed

Question 11

Why is a stabiliser used in plastics?

Answer 11

Stabilisers are used to reduce the effects of ultraviolet light I.e.by making the plastics more resistant to being broken down by sung light .

Question 12

What is hips used for and why?

Answer 12

Used-toys and refrigerators linings

Properties-good Impact resistance,good strength and stiffness,lightweight

Question 13

What is polystyrene used for and why?

Answer 13

Useful-packaging,disposable cups

Why-lightweight,rigid,colourless,low impact strength,

Question 14

What is LDPE used for and why?

Answer 14

Uses-detergent bottles,toys,and carrier bags

Why-
Low density,low stiffness and rigidity,good chemical resistance.

Question 15

What is uPVC used for and why?

Answer 15

Uses-pipes,guttering ,bottles and window frames

Why-good chemical resistances,good resistance to weathering,rigid,hard,tough,lightweight,can be coloured

Question 16

What is the use of PMMA and why?

Answer 16

Uses-light units,illuminated signs,lenses for car lights

Why-good safe,tough,hard,durable,easily machined.

Question 17

What is the use of polypropylene and why?

Answer 17

Uses-kitchen products,medical equipments,string and rope

Why-lightweight,food safe,good impact resistance even at low temperatures,good chemical resistance.